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Carboxylic acid containing dispersants for composites

Inactive Publication Date: 2008-05-29
DENTSPLY SIRONA INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although these materials showed certain improvements on the filling materials used up to that time, the polymer was soft and exhibited very high wear and shrinkage.
Shrinkage of a dental filling material on curing has the consequence that the filling pulls away from the tooth surface on curing, and forms a gap between the filling and the tooth.
Bacteria and fluids are able to penetrate between the filling and the tooth, which often leads to renewed decay of the tooth.
The upper filler content of a composite is however generally limited because with high filler levels the composite material becomes too stiff.
In extreme cases it is difficult or impossible to form a homogenous paste, and even if a paste is obtained it may be too stiff to be used.
One problem with dental composite filling materials is therefore to obtain pastes with high filler loading, while still retaining a consistency that allows easy use.
As demonstrated in the examples, such phosphate esters have a very low pH which is deleterious to some dental glasses.
The filler load achieved in U.S. Pat. No. 6,300,390 is, however, insufficient and does not provide for high mechanical strength after polymerization.
It is another problem to provide a polymerizable dental composite having an increased filler load and, good handling properties and giving, upon polymerization, a polymerized dental composite having good physical properties.

Method used

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  • Carboxylic acid containing dispersants for composites
  • Carboxylic acid containing dispersants for composites
  • Carboxylic acid containing dispersants for composites

Examples

Experimental program
Comparison scheme
Effect test

synthesis example 1

HPGM

[0075]Glutaric anhydride (22.8 g), hydroxypropylmethacrylate (28.8 g), butylated hydroxytoluene (BHT) (0.05 g), and benzyltriethylammonium chloride (TBAC, 0.05 g) were warmed and stirred in a closed flask to 40° C. until a homogenous liquid was obtained. The temperature was then raised to 100° C. for 9 hours. After this time an FTIR spectrum of the mixture had only a very small peak due to the anhydride, and showed that the anhydride had therefore essentially completely reacted. A colourless clear liquid was obtained and was used without further purification. When applied to moistened pH indicator sticks (Machery-Nagel pH-Fix 0.0-6.0) a pH of 2.5 was indicated.

synthesis example 2

GGDM

[0076]A mixture of glutaric anhydride (22.8 g), glycerine dimethacrylate (46.8 g), BHT (0.05 g), and concentrated H2SO4 (0.3 g) was warmed to 40° C. for 2 hours then left to stand for 48 hours. After this time no anhydride remained, as shown by FTIR spectroscopy, and a colourless clear liquid was obtained.

[0077]In a repeat synthesis, a mixture of glutaric anhydride (22.8 g), glycerine dimethacrylate (46.8 g), BHT (0.05 g), and dimethylaminopyridine (0.07 g) was stirred and heated at 50° for 1 hour then the temperature was raised to 100° C. for 2.5 hours. A colourless clear liquid was obtained which contained only a trace of anhydride. When applied to moistened pH indicator sticks (Machery-Nagel pH-Fix 0.0-6.0) a pH of 2.5 was indicated.

synthesis example 3

The Adduct of Glutaric Anhydride with Pentaerythritol Triacrylate

[0078]Glutaric anhydride (22.8 g), pentaerythritol triacrylate (85% purity, 61.15 g), BHT (0.05 g), and concentrated H2SO4 (0.15 g) were stirred and heated to 40° C. for 2.5 hours. After this time FTIR showed that all the —OH groups from the pentaerythritol triacrylate (PTA) had been consumed but that unreacted anhydride remained. A further 25.6 g of PTA and 0.15 g concentrated H2SO4 was added and the mixture left to stand for one day. After further heating to 50° C. for approximately 4 hours a viscous cloudy liquid was obtained.

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Abstract

Polymerizable dental composite comprising a solid filler and an organic polymerizable matrix, said polymerizable matrix comprising:(i) a polymerizable (meth)acrylic monomer having at least two polymerizable groups and(ii) from 1.0 to 15 weight-% of a polymerizable monomer having a carboxylic acid group based on the total weight of said polymerizable matrix.

Description

FIELD OF THE INVENTION[0001]This invention relates to a resin-based polymerizable dental composite having a high filler loading. Further, this invention relates to new polymerizable compounds having a carboxylic acid group. Further this invention relates to a method of producing a polymerizable resin-based dental composite. Moreover, the invention relates to a method of preparing a dental restoration and to a dental composite obtained by polymerizing the polymerizable dental composite filling material of the invention.BACKGROUND TO THE INVENTION[0002]The first polymer based (resin-based) dental filling materials essentially comprised unfilled polymethylmethacrylate. Although these materials showed certain improvements on the filling materials used up to that time, the polymer was soft and exhibited very high wear and shrinkage. A further improvement in properties of the polymer based filling materials was obtained when an inorganic filler was incorporated into the polymer, and this ...

Claims

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Application Information

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IPC IPC(8): A61K6/083
CPCA61K6/083C04B26/06C04B2111/00836C04B14/06C04B14/22C04B14/30C08L33/00A61K6/887
Inventor BLACKWELL, GORDON B.FACHER, ANDREAS
Owner DENTSPLY SIRONA INC